If you’re interested in growing various types of outdoor cacti, you might be wondering which species are the best fit for your climate zone and soil type. You may think that cacti will only thrive in the driest, hottest regions, but there are plenty of species that grow well in semi-arid zones and a couple that even thrives in tropical regions! With over 1,500 species of cacti, it’s important to know which species will fare best outside in your area.
Well, you’ve come to the right place in your quest to choose the right cactus for your landscape! In this guide, we’ll cover four types of outdoor cacti, their botanical classification, characteristics, and their care requirements.
So, without further ado, let’s dive right in!
Cacti: Botanical Classification and a Brief Intro
All cacti belong to the Cactaceae family, which is a family within the larger group of succulent plants. Like other succulents, cacti are masters of conserving water and surviving in more arid environments. Within the Cactaceae family, there are about 130 genera and over 1,500 diverse species. Types of outdoor cacti can take on a variety of forms from tall columnar plants such as the famous saguaro cactus, to small, spiky globed specimens such as the golden barrel cactus.
You may have seen “cacti” and “succulents” used interchangeably. It’s important to understand that cacti are a type of succulent plant, but that there are many other types of succulents that aren’t cacti. So, what distinguishes a cactus plant from other succulents? While most succulents store water in thickened leaves, cacti tend to lose their leaves after their seedling stage, and instead, store water in thickened, modified stems that emerge in the form of cylinders, pads, or joints.
Additionally, unlike other succulents, the vast majority of cacti have modified leaves in the form of spines or tiny spiky hairs called glochidia (many species have both) that help protect against the blazing desert sun, prevent water loss, and defend against predation. A third defining trait unique to cacti is the presence of small cushion-like nodes called areoles. All cacti have areoles and they are the structure from which flowers, spines, and glochidia emerge.
4 Types of Outdoor Cacti: Characteristics and How to Grow
To grow various types of outdoor cacti year-round, you’ll need to live in a climate zone that is suitable for that species of cactus. For most, but not all, cacti, this means living in an arid or semi-arid environment characterized by heat and limited rainfall. One of the fastest ways to kill otherwise hardy cacti is overwatering, which rapidly leads to root death.
Below, we’ll discuss four types of outdoor cacti and their specific growing requirements needed to thrive.
1. Spineless Prickly Pear Cactus (Opuntia cacanapa ‘Ellisiana‘)
The spineless prickly pear cactus (Opuntia cacanapa ‘Ellisiana‘) is among the types of outdoor cacti that are excellent for growing at home. While there are about 100 species of prickly pear cactus (Opuntia), this cultivated species originated in South Texas and Northern Mexico, where it is widely commercially grown to sell for its edible pads and fruits.
The spineless prickly pear is also widely grown as an ornamental since it is typically both beautiful and free of glochidia and spines, making it safe to handle. A word of caution, if you’re truly invested in obtaining a cultivar that has virtually no spines or glochidia, you’ll need to do some research on plant nurseries. Some places that sell this cultivar claim their stock has neither spines nor glochidia, while others say their ‘Ellisiana’ cultivar has no spines but still has glochidia. Remember, these tiny hair-like spikes are highly irritating to the skin.
In the spring, the spineless prickly pear produces clusters of yellow cup-shaped flowers that give way to deep red, delicious fruit.
For best results growing your spineless prickly pear ‘Ellisiana’ cactus, follow the below guidelines:
- Use sandy, gritty, well-draining soil ideally amended with perlite for additional drainage and aeration.
- Provide at least 6 hours of full sunlight year-round. This species tolerates light shade, especially in arid, hot climates.
- Regularly water during its growing phase, which amounts to about once every 7-10 days, allowing the top 2-3 inches of soil to completely dry between watering. During the fall-winter, water about once per month.
- Grow outside only if temperatures remain above 15 degrees Fahrenheit during the winter.
- Ideally, provide a humidity range between 30-40%.
2. Types of Outdoor Cacti: Claret Cup Cactus (Echinocereus triglochidiatus)
The claret cup cactus (Echinocereus triglochidiatus) makes for an excellent addition to outdoor landscapes. This beautiful desert plant produces groups of columnar stems that can grow up to 3 feet high and 6 feet wide. The columns are lined with yellow areoles from which clusters of spines emerge.
Cup-shaped, bright orange-red flowers emerge on the tops of the stems in early spring. The bright orange fruits arrive in summer and are wonderfully tart and sweet. This species is particularly popular as a landscape plant throughout its native range of the arid regions of Southwest and Western US.
For best results growing the claret cup cactus, follow the below guidelines:
- Use a particularly well-draining, gritty cactus potting mix.
- Provide at least 6 hours of full sunlight.
- During its growing season, water regularly but allow the soil to completely dry in between watering.
- During its dormant season, only water thoroughly once at the start of the cold months.
- Grow outside only if temperatures rarely drop below 0 degrees Fahrenheit during the winter.
- Ideally, provide less than 30% humidity.
3. Peanut Cactus (Echinopsis chamaecereus)
If you’re looking for types of outdoor cacti to fill in space in your garden or to hang on your porch in baskets, the peanut cactus (Echinopsis chamacereus) is a great choice. This eye-catching species grows in extremely dense, numerous clusters of columnar stem that branch out in all directions. Each column is covered in many white areoles from which glochidia emerge.
In the late spring, bright red or orange flowers bloom during the day and close up at night.
For best results growing the peanut cactus, follow the below guidelines:
- If potting outside, use extremely well-draining cactus soil. If planting directly into the ground, plant in sandy, gritty soil.
- Plant in a location that receives at least 6 hours of direct sunlight.
- During its growing phase, water regularly but allow the soil to completely dry out between watering. During the winter, cut back to watering about once per month.
- Grow outside only in regions that don’t regularly drop below 40 degrees Fahrenheit.
- Ideally, provide humidity ranges between 20-40%.
4. Saguaro Cactus (Carnegiea gigantea)
For gardeners looking for tree-like plants to fill in a desert yard, the saguaro cactus (Carnegiea gigantea) is a fantastic choice. Regarding types of outdoor cacti, this species is one of the most recognizable and representative plants of the Sonoran Desert.
This cactus grows as a column with smaller columns branching off the center. This species is extremely slow-growing and slow to mature, with the first blooms typically appearing after 35 years and the first arms emerging after 60 years. At 150 years old, the saguaro cactus can reach heights of 40-75 feet.
If you aren’t lucky enough to already have large saguaro cactus in your landscape, you can have specimens at least 6 feet tall transplanted into your yard.
To help your saguaro cactus thrive, follow these growing guidelines:
- Grow in well-draining, sandy, and gritty soil.
- Plant in a location that receives at least 6 hours of full sunlight.
- Water during its growing season only when the soil is completely dry. Don’t water from late fall-winter.
- Only grow in locations that don’t consistently drop below 20 degrees Fahrenheit.
- Grow in a humidity range between 10-30%.
Summary of 4 Types Of Outdoor Cacti
|Spineless Prickly Pear Cactus
|South Texas and Northern Mexico
|Claret Cup Cactus
|Southwest and Western U.S.
The photo featured at the top of this post is © iStock.com/Nahhan
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